Intracorneal Rings and the Barbara Ring
By Dr. Adel Barbara, MD, FRCOphth — Ophthalmologist, Cornea & Refractive Surgery
Last medically reviewed: September 2026
Intracorneal ring segments (ICRS) are implanted in the peripheral corneal stroma to alter corneal shape. Their role is visual rehabilitation—not direct control of keratoconus progression.
What can ICRS achieve?
In a suitable eye, ring segments may flatten or regularize part of the cornea, reduce irregular astigmatism and improve spectacle- or contact-lens-corrected vision. The response is variable and cannot be guaranteed.
The Barbara Ring
The Barbara Ring is a variable-thickness PMMA intracorneal segment designed by Dr. Adel Barbara. Its thickness increases toward the segment’s central region and then decreases, allowing the thickest part to be aligned with the steepest area of an asymmetric cone. This creates a more phenotype-oriented treatment plan.
Who may be suitable?
Important factors include corneal clarity and thickness, cone position, visual potential, contact-lens tolerance and prior CXL. Advanced central scarring may make another approach more appropriate.
ICRS, CAIRS and CXL are not interchangeable
PMMA ICRS and CAIRS aim primarily to regularize the cornea and improve functional vision. CXL aims primarily to stabilize progressive ectasia. A patient may need one approach, a staged combination, or neither.
Risks
Possible complications include infection, glare, migration, extrusion, corneal thinning over a segment, residual irregularity and need for repositioning or removal. Individual planning and follow-up are essential.
Professional source
General information only; treatment selection requires examination.
